The base is original from the producer (chords and melodies), but is complemented with elements that complement the song that come from samplepacks, usually, vocal chops, guitars, wobbles sections, glitch effects. It is the standard in which most of producers work, in a project you will find MIDI files made by the producer, but also melodic loops.
I used Serum as the pad and one shot 808. Except for the battery, fx, and atmosphere, which were used samples.
Sample pack Dropgun Samples Modern - Trap World
Loop name MTW_loop_melodic_musicbox_6_110_Gmin